Jet lag forecaster

ABSTRACT

Alertness level is predicted on computers or sliding charts by relationship of sleep drives and wake drives, which are separately moved relative to destination time and time zone differential. Wake drives are moved with home time. Sleep drive is moved with bedtime and sleep debt relative to times and a sleep debt scale, respectively. Resulting displays predict alertness, drowsiness, wake drives in relation to sleep drives, best bedtime, sleep debt and illumination recommendations.

BACKGROUND OF THE INVENTION

[0001] All humans go through their lives alternating between the statesof sleep and wakefulness. The sleep state is further divided intonon-rapid eye movement sleep (NREMS) and rapid eye movement sleep(REMS). The three states, NREMS, REMS, and wakefulness form a Troika ofConsciousness Cycle (TCC). Mechanisms in the brain control sleep andalertness in a rhythmic manner, producing the same basic pattern everytwenty-four hours, typically eight hours asleep and sixteen hours awake.This daily cycle, or circadian rhythm, is modified by external events:in particular by high speed air travel traversing several time zones.There is a need for better means of predicting the effects of air travelon the circadian rhythm so that travelers can better plan theiractivities to compensate for the changes which result from such travel.

SUMMARY OF THE INVENTION

[0002] The invention can be encapsulated in a computer program or otherembodiment, such as a nomogram. The present invention is a Jet LagForecaster (JLF), Jet Logger, that helps to plan a traveler's activitiesto take advantage of his/her high and low energy periods which occur atstrange times following a long jet flight in a generally east-westdirection.

[0003] The photo zones east and west are important features of theinvention. They indicate the effect that light, either sunlight orartificial, has on the movement of the circadian wake drive in thenychthemeron (a 24 hour period). If a person is exposed to light when aphoto zone is over the current time at destination, his circadian wakedrive will be accelerated in the direction of the photo zone's arrow.These zones are very important indicators of when to avoid light as wellas when to seek light after arriving at the destination.

[0004] The lengths and heights of these zones are very carefully drawnto indicate the duration and strength of light's effect on the circadianwake drive. The closer the exposure is to the wake nadir, the strongerthe effect of the light. However, within a half hour on either side ofthe wake nadir it is difficult to tell in which direction light willpush the circadian wake drive. After the photo zone west tapers down,light has a nil effect on the placement of the circadian wake driveuntil photo zone east starts to build up.

[0005] The invention includes a method and apparatus to predict and planactivity levels after rapid changes in time zones, a method toaccelerate the movement of the circadian wake drive toward local timeand a method to prevent inadvertent movement of the circadian wake driveaway from local time, all for providing more rapid recovery from jetlag.

[0006] These and further and other objects and features of the inventionare apparent in the disclosure, which includes the above and ongoingwritten specification, with the claims and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 shows a Jet Logger chart made of moveable transparentoverlays showing times, time zone shift, sleep and wake drives, sleepdebt, bedtime and wake nadirs, with the sleep debt level and time zoneindicator both at zero.

[0008]FIG. 2 shows a Jet Logger chart similar to FIG. 1, showingincreased sleep debt and sleep drive with the time zone shift indicatorat zero and the sleep debt level at 3.

[0009]FIG. 3 shows a Jet Logger chart similar to FIG. 2 with the timezone indicator at zero and the sleep debt level at three hours and withvaried psycho-sensory wake drive and deepened wake nadir.

[0010]FIG. 4 shows a Jet Logger chart with showing effects of a threehour easterly time zone indicator shift and the sleep debt level at twohours.

[0011]FIG. 5 shows a Jet Logger chart similar to FIG. 4 showing effectsof lessening of sleep debt with the time zone indicator shifted threehours to the east and the sleep debt level at one hour.

[0012]FIG. 6 shows a Jet Logger chart similar to FIG. 5 showing effectsof increasing of sleep debt with the time zone indicator shifted threehours to the east and the sleep debt level at four hours.

[0013]FIG. 7 shows a Jet Logger chart similar to FIG. 5 showing effectsof increasing of sleep debt with the time zone indicator at a two houreasterly shift and the sleep debt level at four hours.

[0014]FIG. 8 shows a Jet Logger chart similar to FIG. 7 with the timezone indicator shifted two hours to the east and the sleep debt level atthree hours.

[0015]FIG. 9 shows a Jet Logger chart with the time zone shift indicatorat zero and the sleep debt level at four hours.

[0016]FIG. 10 shows a Jet Logger with the time zone shift indicator atnine hours to the east and the sleep debt level at four hours.

[0017]FIG. 11 shows a Jet Logger chart with the time zone shiftindicator at nine hours to the east and the sleep debt level at sevenhours showing effects on the drives and nadir of increased sleep debt.

[0018]FIG. 12 shows a Jet Logger chart with the nine hour time zoneshift and the sleep debt level at three hours.

[0019]FIG. 13 shows a Jet Logger chart with the time zone indicator atseven hours east and the sleep debt level at four hours.

[0020]FIG. 14 shows a Jet Logger chart with the time zone indicator atfive hours east and the sleep debt level at six hours.

[0021]FIG. 15 shows a Jet Logger chart with the time zone indicator atfive hours east and the sleep debt level at four hours.

[0022]FIG. 16 shows a Jet Logger chart with the time zone indicator atthree hours east and the sleep debt level at six hours.

[0023]FIG. 17 shows a Jet Logger chart with the time zone indicator atthree hours east and the sleep debt level at four hours.

[0024]FIG. 18 shows effects on a Jet Logger chart with the time zoneindicator at one hour east and the sleep debt level at six hours.

[0025]FIG. 19 shows a Jet Logger chart similar to FIG. 18 with the timezone indicator at one hour east and the sleep debt level at five hours.

[0026]FIG. 20 shows a Jet Logger chart with the time zone indicator atsix hours west and the sleep debt level at two hours.

[0027]FIG. 21 shows a Jet Logger chart with the time zone indicator atsix hours west and the sleep debt level at seven hours.

[0028]FIG. 22 shows a Jet Logger chart with the time zone indicator atfour hours west and the sleep debt level at six hours.

[0029]FIG. 23 shows a Jet Logger chart with the time zone indicator atthree hours west and the sleep debt level at five hours.

[0030]FIG. 24 shows a Jet Logger chart with the time zone indicator attwo hours west and the sleep debt level at four hours.

[0031]FIG. 25 shows a return to near normal with the time differentialdisplaced only one hour.

[0032]FIG. 26 shows a chart base with a sleep debt scale, a time atdestination indicator and a time zone indicator.

[0033]FIG. 27 shows a transparent overlay for moving left and right witha home time indicator, wake drive indicators and a time zone selector.

[0034]FIG. 28 shows a second transparent overlay for moving up and downand left and right with sleep drive, sleep debt, sleep point, and sleeptime indicators.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] How to Use the Jet Logger

[0036] Referring to FIGS. 1-27, the Jet Logger 1 will make the next tripa more rewarding experience. One will be able to plan the activities totake advantage of the high and low energy periods that occur at strangetimes after a jet flight. The purpose of these instructions is simply toshow one how to adjust the Jet Logger 1. They will give only minimaladvice on the nature and timing of activities one can do before takingoff, during flight, and after landing to minimize or compensate for theaccompanying unwanted symptoms. When and how to use these activitieswill depend upon business, competition or pleasure priorities. Armedwith this knowledge, the Jet Logger 1 is a powerful tool to ensure arewarding trip.

[0037] Once one knows what the different lines and shapes represent, andunderstands a few simple principles, adjusting the Jet Logger 1 isintuitive. Keep the instrument handy while reading these instructions inorder to repeat the example adjustments.

[0038] These instructions assume a normal sleep-wake cycle and a usualwake up time and bedtime within an hour and a half of 7:00 am and 11:00pm.

[0039] Lines and Shapes

[0040] AS shown in FIGS. 1-24, a person has two wake drives 3 and 5 thatwork together trying to make the person alert and one sleep drive 7 thattries to make the person sleep. These drives compete with each other fordominance over a person twenty-four hours a day. Only the one on topdetermines whether the person is awake or asleep.

[0041] The circadian wake drive 3 is the dark line that undulates acrossthe chart 21. It rolls along the same up and down path at the same timeevery day as long as one stays in the same time zone. When a personlands in a new time zone, that person's circadian wake drive 3 willstill be rolling along in time with the clock at home, but it will startshifting to conform to the new local time. This shift usually occurs atthe rate of one time zone per day. Until this change is complete, aperson will be experiencing jet lag.

[0042] The psycho-sensory wake drive 5 is the dark line covering thecircadian wake drive. The psycho-sensory wake drive 5 can expand toreinforce the circadian wake drive when a person wants to stay awake, orit can contract when a person wants to sleep. Its strength can vary fromminute to minute as shown in FIG. 3 depending upon the amount ofstimulation it gets from a person and the person's environment.

[0043] The sleep drive 7 is the dark wave-like area. The sleep drive'sstrength is determined only by the amount of sleep a person gets. Asleep drive 7 increases while a person is awake and decreases while aperson is asleep. As seen by comparing FIGS. 1 and 2, a sleep drive 7increases as sleep debt 17 increases.

[0044] The time zone indicator 11 is the triangle on the time zone scale13 at the bottom of the chart 21. Sliding the time zone indicator 11right or left indicates the direction and number of time zones a personwill cross on a trip. If no anti jet lag measures are taken, after eachday at destination move time zone indicator 11 back one time zonetowards the center.

[0045] The bedtime indicator 15 is the vertical line passing through thepeak 9 of the wave-shaped sleep drive 7. Using 11:00 pm as bedtime athome, a person obtains a good jet lag forecast if regular bedtime is ata destination within an hour and a half of that time.

[0046] The sleep debt level 17 is a horizontal bar passing through thepeak 9 of the sleep drive 7.

[0047] The sleep debt scale 19 is the rectangular grid in the top halfof the chart 21. The number of hours of insufficient sleep is recordedas sleep debt by moving the sleep debt level 17 upward on this scale.

[0048] The sleep point 23 is where the bedtime indicator 15 crosses thetop of the sleep debt level 17. Sleep point 23 indicates a person'ssleep debt level 17 on sleep debt scale 19 at bedtime 15. The later aperson goes to bed, the larger the person's sleep debt. Likewise theearlier a person goes to bed, the smaller it is. Therefore, to keep thesleep point 23 in its proper place, a person must move the sleep debtlevel 17 up or down as many rows as the number of hours the bedtimeindicator 15 is moved right or left respectively.

[0049] The wake nadir 25 is the small triangle at the lowest point onthe circadian wake drive 3. It indicates the most difficult time to stayalert. At home, the wake nadir 25 usually occurs between 4:00 and 5:00am, but after jet travel it can occur at any hour.

[0050] The photo zones east 27 and west 29 are the two light curvescovering arrows 31 and 33 just before and just after the wake nadir 25.Exposure to light during the time zones covered by either of these photozone curves 27, 29 will shift the circadian wake drive 3 in thedirection indicated by the related arrow 31, 33. The closer the lightexposure is to the wake nadir 25 the greater is the shift, however, itis difficult to predict the direction of the shift when the exposure isvery near the wake nadir.

[0051] Accumulation of Sleep Debt

[0052] It is normal to have up to four hours sleep debt 17. A personaccumulates one hour sleep debt for every hour the person sleeps lessthan the usual amount, and a person accumulates a half hour sleep debtfor every one hour of poor quality sleep. However, if a person sleepsmore than the person's usual amount, the person subtracts one hour fromthe person's sleep debt for every extra hour the person sleeps. Whencalculating sleep debt level 17, hours are rounded off to the nearestwhole number.

[0053] At Home with no Sleep Debt

[0054] In FIG. 1, the sleep debt level 17 and time zone indicator 11 areboth at zero. This tells that the person depicted is highly alert, forexample between the hours of 7:00 am and 11:00 pm in his home time zone.The relative heights of the wake drive 3, 5 and sleep drives 7 areimportant. The higher on the chart 21 a wake drive 3,5 or sleep drive 7is, the stronger it is. When a person's wake drives 3, 5 are high abovethe sleep drive 7 the person is very alert. When a person's wake drives3, 5 are close to the sleep drive 7, the person is drowsy. When aperson's sleep drive 7 is above both the wake drives 3, 5, the person isasleep. FIG. 1 shows the ideal position of the circadian wake drive 3relative to the sleep drive 7. Notice that both rise and fall at thesame times.

[0055] In FIG. 1 the sleep drive 7 is below the circadian wake drive 3during all parts of the day. No expansion of the psycho-sensory wakedrive 5 is necessary to stay awake.

[0056] Volatility of the Psycho-Sensory Wake Drive

[0057] The main cause of jet lag is a displaced circadian wake drive 5.The circadian wake drive 5 tends to remain aligned with the at home whena person is at another location or destination in a different time zone.Jet lag is usually aggravated by an excessive sleep debt. A person'spsycho-sensory wake drive 5 neutralizes the symptoms of jet lag byexpanding, as shown in FIG. 3. Its results, however, are not withoutlimit or effort. To help a person understand how the psycho-sensory wakedrive 5 can combat these symptoms, let us first look at how it functionsat home in a normal individual with a three hour sleep debt.

[0058] Move the sleep debt level 17 upward three hours as shown in FIG.2. Notice that the sleep drive 7 is now above the wake drives 3, 5between 7:00 and 8:00 in the morning, 12:30 and 5:00 in the afternoon,and 9:30 and 11:00 at night. This is normal, but if no adjustments aremade to the subject's wake and/or sleep drives the subject would beasleep at these times. The subject cannot immediately change thestrength of his circadian wake drive 3 or his sleep drive 7. It takesdays to change them, but the strength of his psycho-sensory wake drive 5can be changed in seconds, as shown in FIG. 3. Anything that stimulateshim physically or mentally increases its strength. These stimulantsinclude alarm clocks, lights, coffee, physical activity,conversation—the list is endless. There is also a long list of factorsthat decrease its strength, like silence, darkness, alcohol, sleepingpills, physical inactivity, anything monotonous.

[0059] Typical Psycho-Sensory Wake Drive Reactions to Daily Events

[0060] Let's follow the subject from wake up in the morning to bedtimeat night on his birthday (FIG. 3). The subject is awakened at 7:00 am byan alarm clock that shoots his psycho-sensory wake drive 5 above hissleep drive. He gets ready for the day, eats breakfast, and drives towork. Boring paper work causes his psycho-sensory wake drive 5 to diparound 10:00 am, but he won't doze off at this time because hiscircadian wake drive 3 is higher than his sleep drive. An exciting lunchdate at noon perks up his psycho-sensory wake drive 4, but theaftereffects of the luncheon cocktail plus more dull paper work reduceit during mid afternoon. He is very drowsy between 3:00 and 4:00 pm. At5:00 pm his office surprises him with a birthday party. He has dinnerand a glass of wine at 7:00 pm and watches TV the remainder of theevening. His psycho-sensory wake drive 5 gradually declines until 9:00pm when he momentarily dozes off. Immediately after that an excitingmovie appears on TV and he perks up until it ends at 11:00 pm.

[0061] As can be seen, the psycho-sensory wake drive 5 is affected byvarious stimulants and depressants throughout the day. A person cancontrol some of these stimulants but not others. The Jet Logger 1 doesnot show the expansion and contraction of the psycho-sensory wake drive5. A person will know how much wake drive 5 is needed in every hour ofthe day at the destination just by looking at the relationship of thecircadian wake drive 3 to the sleep drive. As the person will see in theexamples below, with reference to FIGS. 4-24, the need forpsycho-sensory wake drive 5 will occur in very different times at thedestination than it does at home.

[0062] The sleep-wake scenarios that a person can encounter when jettraveling are endless, depending upon the direction of travel, thenumber of time zones 12 crossed, the size of the person's sleep debt 17,the person's bedtime 16 and the person's wake up time 18 at destination20. The few examples given below are sufficient to show how to adjustthe Jet Logger 1.

[0063] Jet Logger Adjustments for all Trips

[0064] Before Departure

[0065] 1. Move the sleep debt level 17 to indicate sleep debt at startof trip.

[0066] 2. Move the time zone indicator 11 east or west as many timezones 12 as will be crossed, and return the bedtime indicator 15 to11:00 pm at home time 22.

[0067] On Arrival

[0068] 3. Move the sleep debt level 17 up or down to adjust for amountof sleep during flight. If day flight, reduce sleep debt level 17 onerow for each hour slept. If night flight reduce or increase sleep debtlevel 17 one row for each hour slept more or less than usual night athome respectively.

[0069] First Night After Arrival

[0070] 4. Move the sleep point 23 and bedtime indicator 15 to bedtime atthe destination time 24. Move the sleep point 23 and the sleep debtindicator up or down on the sleep debt scale 19 as many rows as thenumber of hours the bedtime indicator 15 is moved right or leftrespectively.

[0071] First Morning at Destination

[0072] 5. Move the sleep debt level 17 up or down depending on quantityand quality of the last night's sleep. Move the debt level indicator 17upward one hour above the level in step 4 for every hour slept less thanin a usual night at home, and one hour upward for every two hours ofpoor quality sleep. Move the debt level indicator 17 downward one hourfor every hour slept more than in a usual night at home.

[0073] 6. Move the time zone indicator 11 one to two time zones towardszero. Usually, the circadian wake drive 3 returns to normal at the rateof about one time zone per day. Light exposure during the photo zonescan retard or accelerate that rate depending on the direction of theappropriate arrow 31, 33 in the photo zone.

[0074] Each Next Night and Morning

[0075] Repeat steps 4-6 until back to normal sleep-wake schedule and thetime zone indicator 11 is at zero.

[0076] When returning home one repeats the steps 1-6.

[0077] Examples of Jet Logger Adjustments

[0078] Eastbound, Three Time Zones, Daytime Flight

[0079] Before Departure, as Shown in FIG. 4:

[0080] 1. Move the sleep debt level 17 to row 2 to indicate two hours ofsleep debt 17 (assuming the person is alert normal).

[0081] 2. Move the time zone indicator 11 three zones rightward andreturn the bedtime indicator 15 to 11:00 pm at home.

[0082] On Arrival

[0083] 3. No adjustment is made to sleep debt level 17 (assuming persondid not sleep on the flight). The Jet Logger 1 now should look like FIG.4. Notice that 11:00 pm at home time 22 is 2:00 am at destination time20. Also notice that at midnight at destination time 20, the person'ssleep drive 7 is just below the person's circadian wake drive 5. Aperson would have difficulty falling asleep at that time.

[0084] First Night After Arrival

[0085] Let us say the person decides to go to bed at 1:00 am. Look atFIG. 4 to see where the person's sleep drive 7 is at 1:00 am. That iswhere the sleep point 23 must now be moved to, 10:00 pm at home time 22.

[0086] 4. Move the sleep point 23 one hour leftward to 1:00 amdestination time 20 and 1 row downward to indicate one less hour sleepdebt 17 (the hour between 2:00 am and 1:00 am destination time 20). TheJet Logger 1 now should look like FIG. 5.

[0087] First Morning at Destination

[0088] The person sleeps until 7:00 am destination time 20 the nextmorning and the person's sleep debt 17 is larger for two reasons: 1) theperson slept two hours less (1:00 to 7:00) than the usual eight houramount, and 2) the person's Jet Logger 1 indicates (FIG. 5) that thequality of sleep between 1:30 and 2:30 am was poor.

[0089] 5. Move sleep debt level 17 upward three additional hours to row4 (2 for quantity and 1 (one hour halved then rounded upward) forquality of sleep). The Jet Logger 1 should look like FIG. 6. Notice thatthe person needed an alarm to wake up at 7:00 am. Also notice that theperson's wake nadir 25 is now at 7:30 am. Light exposure before thattime moves (arrow 31) the person's circadian wake drive 3 furthereastward. Light exposure after that time would return it to the west.Jet lag is reduced when the triangular time zone indicator 11 at thebottom on the chart 21 moves towards zero. Therefore a person exposeshimself to light when in the photo zone whose arrow point in thedirection that will push or pull the time zone indicator 11 towardszero. The person avoids light when the arrow will move it away fromzero. In that case one tries to avoid light before 7:30 am, and tries toget as much light as possible between 8:00 am and noon.

[0090] 6. Move the time zone indicator 11 one time zone leftward to timezone 2. This person was unable to get out in the bright sunlight, butwas exposed to the equivalent of office lighting. The Jet Logger 1should now look like FIG. 7. Notice that after rising to an alarm at7:00 am a person will need to expand the psycho-sensory wake drive 5 tokeep alert until late morning and during the midday circadian wake drivedip, which will now occur around 5:00 pm. A person will not need muchpsycho-sensory wake drive 5 to be alert around 9:00 pm.

[0091] Second Night

[0092] Repeat step 4. Although FIG. 7 indicates that a person could fallasleep at 11:00 pm, the evening circadian wake drive plateau 5 wouldsoon wake the person up. The person would do better to go to bed atmidnight (10:00 pm at home, time 22).

[0093] 4a. Move the sleep point 23 one hour leftward to midnight and onerow downward to indicate three hours sleep debt. The Jet Logger 1 shouldlook like FIG. 8.

[0094] Second Morning

[0095] Repeat steps 5-6. Except for a brief period between 1:30 and 2:00am last night, the quality of the person's sleep was good, but theperson slept one hour less (12:00 to 7:00) than the usual eight houramount.

[0096] 5a. Move the sleep debt level 17 upward one hour to row 4. Theperson's wake nadir 25 is now at 6:30 am. Since the person slept until7:00 am, the person avoided light before the wake nadir. It was a brightsunny day. The person had breakfast in front of a large window and spentthe entire morning outdoors.

[0097] 6a. Move the time zone indicator 11 two time zones leftward totime zone O. The Jet Logger 1 should now look like FIG. 9. The personshould have no remaining jet lag. The sleep debt level 17 is highnormal, and the person should have no difficulty going to sleep at 11:00pm or an hour earlier to reduce the sleep debt.

[0098] Eastbound, Nine Time Zones, Night Plus Daytime Flight

[0099] A person will depart late afternoon and arrive at the destinationthe next day at 4:00 pm.

[0100] Before Departure

[0101] 1. Move the sleep debt level 17 to row 4 (assuming the person hasa high normal sleep debt).

[0102] 2. Move the time zone indicator 11 nine time zones to the right,and return the bedtime indicator 15 to 11:00 pm at home time 22. The JetLogger 1 should look like FIG. 10. Notice that the person's wake nadir25 is at 1:30 pm destination time 20. During the flight if one issitting next to a window, one should keep the shade down until thattime, then raise it and look at the white clouds. Never look directly atthe sun. One should try to keep exposed to bright light until lateafternoon. From 7:00 pm until 4:00 am, destination time, light exposurewill have negligible effect on the circadian wake drive 3.

[0103] On Arrival

[0104] During the flight the person slept three hours less than theusual amount at home.

[0105] 3. Move the sleep debt level 17 upward three hours to row 7. TheJet Logger 1 now should look like FIG. 11. Notice that 9:00 pm atdestination is noon at home. Since the person has seven hours sleepdebt, the person will not have any difficulty falling asleep any timeafter arrival. But, the circadian wake drive 3 is rising during thattime so the person would not sleep very long. The chances of continuoussleep are slight before 4:00 am, which is 7:00 pm at home. That's whenthe circadian wake drive 3 starts to level off before declining. It isimportant not to nap during this day, since napping would reduce thesleep drive, which is necessary to enable the person to sleep thatnight.

[0106] First Night After Arrival

[0107] Let us say a person decides to go to bed at 4:00 am. Observe inFIG. 11 where the sleep drive 7 will be at that time. That is where thesleep point 23 must now be moved.

[0108] 4. Move the sleep point 23 four hours leftward to 4:00 am andfour rows downward to indicate three hours sleep debt 17.

[0109] The Jet Logger 1 as shown in FIG. 12 tells several importantthings. One is that the person will have a difficult time sleepingbetween 4:30 and 8:00 am. The person may fall asleep quickly at 4:30 am,but will awaken in about a half hour when the sleep drive 7 dips belowthe circadian wake drive 3. Since the photo zone east 27 begins around4:00 am and continues to rise until the wake nadir 25, which occursabout 1:30 pm, it is important that the person avoid light and stayinactive during that time. The sleep drive 7 will show a saw toothpattern above and the circadian wake drive 3 until about 8:00 am. Theperson will then be able to sleep soundly until after the wake nadir 25.Before going to sleep it is important to make the room as light proof aspossible. If one has to awaken before 1:30 pm, wear dark glasses untilthat time.

[0110] First Morning at Destination

[0111] Let us say a person was able to sleep until 8:00 am. The personspent nine hours in bed, but must deduct half of the four hours of poorquality sleep. That leaves the person with a net of seven hours ofsleep, one hour less than usual.

[0112] 5. Move sleep debt level 17 upward one row to level 4. That moveis based on the assumption the person was able to spend most of theafternoon in the sunlight after being in darkness during the photo zoneeast 27. That should cause the circadian wake drive 3 to advance twohours rather than the usual one hour per day.

[0113] 6. Move the time zone indicator 11 two time zones leftward totime zone 7. The Jet Logger 1 should now look like FIG. 13.

[0114] Second Night

[0115] Repeat step 4. Let us say the person is able to resist nappingduring the day and go to sleep again at 4:00 am.

[0116] 4a. No adjustment to bedtime.

[0117] Second Morning

[0118] Repeat steps 5-6. The person sleeps until 11:00 am. That givesthe person seven hours in bed, which is one hour less than the usual.Also the quality of sleep was poor between 4:30 am and 6:30 am.

[0119] 5a. Move sleep debt level 17 upward a total of two hours to level6 (one hour for quantity and one hour for quality of sleep). Notice thatthe person's wake nadir 25 occurred at 11:30 am that morning. Thatassumes that the person got several hours of sunlight between noon and4:30 pm in addition to the darkness before the wake nadir 25. Thatcauses the circadian wake drive 3 to again advance two hours rather thanthe usual one hour.

[0120] 6a. Move the time zone indicator 11 two time zones leftward totime zone 5. The Jet Logger 1 should now look like FIG. 14.

[0121] Third Night

[0122] Repeat step 4. Tonight the person should be able to go to sleepat 2:00 pm.

[0123] 4b. Move the bedtime indicator 15 two hours leftward to 2:00 amand the sleep debt indicator 17 two rows downward to indicate four hourssleep debt. The Jet Logger 1 should look like FIG. 15.

[0124] Third Morning

[0125] Repeat steps 5-6. The person sleeps until 9:00 pm. That againgives the person seven hours in bed, including poor quality of sleepbetween 2:30 and 4:30 am, resulting in two hours increase in sleep debt.

[0126] 5b. Move the sleep debt level 17 upward two hours to level 6.This assumes the person got the optimum darkness and bright light aroundthe wake nadir 25, which occurred that morning at 9:30.

[0127] 6b. Move the time zone indicator 11 two time zones leftward totime zone 3. The Jet Logger 1 should now look like FIG. 16.

[0128] Fourth Night

[0129] Repeat step 4. Tonight the person should be able to go to sleepat midnight.

[0130] 4c. Move the bedtime indicator 15 and sleep point 23 two hoursleftward to midnight and two rows downward to indicate four hours sleepdebt. The Jet Logger 1 should now look like FIG. 17, which is similar toboth FIGS. 13 and 15. The only difference is the circadian wake drive 3is four hours ahead of that in FIG. 13 and two hours ahead of that inFIG. 15. That enables the person to go to sleep two hours earlier thanthe previous night.

[0131] Fourth Morning

[0132] Repeat steps 5-6. The person sleeps until 7:00 pm. That againgives the person seven hours in bed, including poor quality of sleepbetween 12:30 and 2:30 am, resulting in two hours increase in sleepdebt.

[0133] 5c. Move the sleep debt level 17 upward two hours to level 6.That assumes the person gets the optimum darkness and bright lightaround the wake nadir 25, which occurred that morning at 7:30 am.

[0134] 6c. Move the time zone indicator 11 two times zone leftward totime zone 1. The Jet Logger 1 should now look like (FIG. 18)

[0135] Fifth Night

[0136] Repeat step 4. Tonight the person should be able to go to sleepat 11:00 pm.

[0137] 4d. Move the bedtime indicator 15 and sleep point 23 one hourleftward to 11:00 pm and one row downward to indicate five hours sleepdebt. The Jet Logger 1 should now look like FIG. 19.

[0138] Fifth Morning

[0139] Repeat steps 5-6. The person got the normal quantity and qualityof sleep last night.

[0140] 5d. No adjustment to sleep debt.

[0141] 6d. Move the time zone indicator 11 one time zone leftward totime zone 0.

[0142] Sixth Night

[0143] The person's circadian rhythm is back to normal, so the person isnow able to go to bed earlier than the usual time at home if the personwould like to reduce the sleep debt.

[0144] Westbound, Six Time Zones, Daytime Flight

[0145] Let us assume a person will arrive at the destination earlyevening.

[0146] Before Departure

[0147] We assume the person has a high normal sleep debt.

[0148] 1. Move the sleep debt level 17 to the four hour level.

[0149] 2. Move the time zone indicator 11 six time zones to the left,and return the bedtime indicator 15 to 11:00 pm at home.

[0150] On Arrival

[0151] During the flight the person slept two hours.

[0152] 3. Move the sleep debt level 17 downward two hours to row 2. TheJet Logger 1 should look like FIG. 20. Notice that 11:00 pm at home time22 is 5:00 pm at destination time 20. Although the person can fallasleep any time after 5:00 pm, it is not advisable to do so since theperson would then have difficulty sleeping beyond 2:00 am. The personshould try to stay up until 10:00 pm (4:00 am at home) gaining as muchexposure to bright light as possible up to but not beyond that time(10:00 pm) since the wake nadir 25 is at 10:30 pm.

[0153] First Night After Arrival

[0154] Let us say the person goes to bed at 10:00 pm. Look at FIG. 20 tosee where the person's sleep drive 7 will be at that time. That is wherethe sleep point 23 must now be moved. Remember every one hour thebedtime indicator 15 is moved rightward the sleep debt level 17 must bemoved one row upward.

[0155] 4. Move the sleep point 23 five hours rightward to 10:00 pm andfive rows upward to indicate seven hours sleep debt. The Jet Logger 1should look like FIG. 21.

[0156] First Morning at Destination

[0157] Assume the person sleeps until 7:00 am. The person received onehour more than the usual amount of sleep.

[0158] 5. Move sleep debt level 17 downward one hour to row 6. Thatassumes the person got ample bright light before going to bed at 10:00pm and slept in darkness after the wake nadir 25 at 10:30 pm.

[0159] 6. Move the time zone indicator 11 two hours rightward to timezone 4. The Jet Logger 1 should look like FIG. 22.

[0160] Second Night

[0161] Repeat step 4. The person goes to sleep at 10:00 pm.

[0162] 4a. No adjustment to sleep point.

[0163] Second Morning

[0164] Repeat steps 5-6. The person again sleeps nine hours until 7:00pm.

[0165] 5a. Move sleep debt level downward one hour to level 5. Theperson's wake nadir 25 occurred at 12:30 am, and the person was unableto be exposed to bright light several hours prior to it.

[0166] 6a. Move the time zone indicator 11 one hour rightward to timezone 3. The Jet Logger 1 should look like FIG. 23.

[0167] Third Night

[0168] Repeat step 4. The person again goes to sleep at 10:00 pm.

[0169] 4b. No adjustment to sleep point.

[0170] Third Morning

[0171] Repeat steps 5-6. The person again sleeps nine hours until 7:00pm.

[0172] 5b. Move sleep level downward one hour to level 4.

[0173] 6b. Move the time zone indicator 11 one time zone rightward totime zone 2. The Jet Logger 1 should look like FIG. 24.

[0174] Fourth Night

[0175] Repeat step 4. FIG. 24 indicates that the person's energy levelsduring the day are approximately normal except for the late evening. Theperson should now be able to go to sleep at 9:00 pm and sleep until 7:00am.

[0176] 4c. Move sleep point 23 one hour leftward to 9:00 pm and one rowdownward to indicate three hours of sleep debt.

[0177] Fourth Morning

[0178] Repeat steps 5-6. The person slept two hours more than the usual.

[0179] 5c. Move sleep debt level 17 downward two hours to level 1.

[0180] 6c. Move the time zone indicator 11 one time zone rightward totime zone 1. The Jet Logger 1 should look like FIG. 25.

[0181] Fifth Night

[0182]FIG. 25 indicates that the person's energy levels are now high allday and late evening. The person should be able to go back to theregular 11:00 pm to 7:00 am sleep schedule.

[0183] Referring to FIG. 26 a chart base 51 has a sleep debt scale 19, atime at destination indicator 20 and a time zone indicator 11.

[0184] Referring to FIG. 27 a transparent overlay 53 overlies the chartbase 51 and moves left and right. Overlay 53 has a home time indicator22, lines to represent wake drives 3 and 5 and a time zone selector 11.

[0185] Referring to FIG. 28 a second transparent overlay 55 overlieschart base 51 and overlies or underlies transparent overlay 53 and movesup and down and left and right. Transparent overlay 55 has a transparenthatched wave shape to show sleep drive 7, and has sleep debt indicator17, sleep point indicator 23, and bedtime indicator 15.

[0186] Assembling the base chart 51 and overlays 53 and 55 forms thecharts 1 of FIGS. 1-25.

[0187] A frame, not shown holds the overlays on the chart to form anadjustable Jet Lag Forecaster 1.

[0188] The base chart and overlay are preferably reproduced in softwarein a computer so that a hard drive or replaceable drive may be used witha laptop or hand-held computer to chart, predict, and record sleep andwake drive relationships and times of effectiveness.

[0189] While the invention has been described with reference to specificembodiments, modifications and variations of the invention may beconstructed without departing from the scope of the invention, which isdefined in the following claims.

I claim:
 1. A method of predicting sleep and activity levels, comprisingproviding a chart, providing lines and shapes representing personaldaily wake drives and a sleep drive, providing on the chart indicationsof time of day at a starting location, providing on the chartindications of time of day at a destination location, displaying on thechart personal daily wake drives and sleep drives related to the time ofday at the starting location and the time of day at the destination. 2.The method of claim 1, wherein the displaying further comprises movingrelative positions of the wake drives and the sleep drives.
 3. Themethod of claim 2, wherein the moving further comprises dailyreadjusting the relative positions.
 4. The method of claim 3, whereinthe daily readjusting further comprises moving the wake drive and thesleep drive lines and shapes in a direction of the time of day at thedestination.
 5. The method of claim 1, wherein the wake drives arerepresented by undulating lines across the indications of time.
 6. Themethod of claim 1, wherein the sleep drive is indicated by a peakingshape across the time of day indications on the chart.
 7. The method ofclaim 1, wherein the presenting of lines and shapes further comprisesproviding curved lines representing circadian wake drive and psychosensory wake drive.
 8. The method of claim 1, wherein the presenting oflines and shapes further comprises providing a wave-like shape having acrest and troughs representative of the sleep drive.
 9. The method ofclaim 8, wherein the presenting of lines and shapes further comprisesproviding a transverse line through the crest representing a bedtimeindicator.
 10. The method of claim 8, wherein the presenting of linesand shapes further comprises providing a V-shaped curve preceding abottom of the trough representing a wake nadir.
 11. The method of claim10, wherein the presenting of lines and shapes further comprisesproviding sloped curves leading toward and away from the V-shaped curverepresenting photo zone east and photo zone west.
 12. The method ofclaim 1, wherein the providing of times of day further comprisespresenting dark and light areas in the time of day representing dark andsunlight hours during days.
 13. The method of claim 1, furthercomprising providing an indication on the chart of time zones west andtime zones east.
 14. The method of claim 1, further comprising providingon the chart a sleep debt scale.
 15. The method of claim 14, furthercomprising providing on the chart a sleep debt level.
 16. Apparatuspredicting sleep and activity levels, comprising a chart, relativelymoveable lines and a shape on the chart representing personal daily wakedrives and a sleep drive, relatively moveable indications of time of dayat a starting location on the chart, indications of time of day at adestination location on the chart for displaying on the chart personaldaily wake drives and sleep drives related to the time of day at thestarting location and the time of day at the destination and movingrelative positions of the wake drives and the sleep drives.
 17. Theapparatus of claim 16, wherein the wake drives are represented byundulating lines across the indications of time.
 18. The apparatus ofclaim 16, wherein the sleep drive is indicated by a peaking shape acrossthe time of day indications on the chart.
 19. The apparatus of claim 17,wherein the lines further comprise curved lines representingrespectively circadian wake drive and psycho sensory wake drive.
 20. Theapparatus of claim 16, wherein the shape further comprises a wave-likeshape having a crest and troughs representative of the sleep drive. 21.The apparatus of claim 20, wherein the lines further comprise atransverse line through the crest representing a bedtime indicator. 22.The apparatus of claim 20, wherein the lines further comprise a V-shapedcurve preceding a bottom of the trough representing a wake nadir. 23.The apparatus of claim 22, wherein the lines further comprise slopedcurves leading toward and away from the V-shaped curve and respectivelyrepresenting photo zone east and photo zone west.
 24. The apparatus ofclaim 16, wherein the providing of times of day further comprisespresenting dark and light areas in the time of day indications forrepresenting dark and sunlight hours during twenty-four hour periods.25. The apparatus of claim 16, wherein the lines further comprise anindication on the chart of time zones west and time zones east.
 26. Theapparatus of claim 16, further comprising a sleep debt scale on thechart and a relatively moveable sleep debt level line on the chart. 27.Apparatus for predicting sleep and activity levels for changingcircadian rhythms comprising a chart having a sleep debt scale andhaving time zone west and east indications and time at destinationindications, a first relatively moveable overlay having time at homeindications, curved lines respectively representing circadian andpsycho-sensory wake drives and a mark for aligning with a selected timezone indications, a second relatively moveable overlay having awave-like representation of sleep drive with a crest at maximum sleepdrive and troughs at minimum sleep drives and having a line through thecrest for representing sleep debt level in relation to the sleep debtscale.
 28. The apparatus of claim 27, further comprising a second linethrough the crest at an angle to the line for representing sleep debtlevel, the second line intercepting the time of day indications forrepresenting bed time.
 29. The apparatus of claim 27, further comprisingrepresentations of wake nadirs on the first overlay at lower portions ofthe wake drive curve.
 30. The apparatus of claim 29 further comprisingslopes and arrows leading and pointing toward the wake nadirsrepresenting respectively photo zones west and east and overlaymovements to be made upon exposure to light during the times of thephoto zones.
 31. The method for predicting and planning activity levelsafter rapid changes in time zones comprising moving representations oftime of day at home, a time zone selector, and wake drives in relationto representations of time of day at destination and time zones cast andwest and aligning the time zone selector with a time zone east or west,moving representation of a sleep drive and a bed time indicator withrespect to the representations of times of day.
 32. The method of claim31, further comprising moving a representation of sleep debt and therepresentations of sleep drive with respect to a sleep debt scale. 33.The method of claim 32, further comprising moving the representation ofsleep debt to a lesser or greater level on the sleep debt scale afterobtaining less or more sleep than usual in twenty four hours.
 34. Themethod of claim 31, further comprising moving the time zone selector onehour toward a middle for each day spent at a destination time.
 35. Themethod for predicting and planning activity levels after rapid changesin time zones comprising providing representations of wake drives inrelation to representations of time of day at destination and time zoneseast and west and providing representations of wake nadirs at lowerportions of the wake drive curve, slopes and arrows leading and pointingtoward the wake nadirs representing respectively photo zones west andeast and effects of exposure to light during times of the photo zones.36. The method of claim 35, further comprising moving therepresentations of wake drives in the directions of the arrows when auser is exposed to light during times of one of the photo zones.
 37. Themethod of claim 35, wherein the providing of slopes and arrows comprisesproviding curved slopes showing increasing in height toward the nadirsand the sloping sharply downward toward the nadirs on both sides of eachnadir and wherein the providing of arrows further comprises providing ofupward sloping arrows within the slowly increasing and sharply downwardcurves on both sides of each nadir.
 38. The method of claim 37, furthercomprising moving the wake drive representations with respect to a timeof day indication according to the height and direction of the arrow ata time of exposure to light near one of the nadirs.
 39. Apparatus forpredicting sleep and activity levels for changing circadian rhythmscomprising a chart having time zone west and east indications and timeat destination indications, curved lines respectively representingcircadian and psycho-sensory wake drives and a mark for aligning with aselected time zone indications, representations of wake nadirs at lowerportions of the wake drive curve, slopes and arrows leading and pointingtoward the wake nadirs representing respectively photo zones west andeast and effects of exposure to light during times of the photo zones.40. The apparatus of claim 39, wherein the slopes and arrows comprisescurved slopes showing increasing in height toward the nadirs and thesloping sharply downward toward the nadirs on both sides of each nadirand wherein the providing of arrows further comprises providing ofupward sloping arrows within the slowly increasing and sharply downwardcurves on both sides of each nadir.